1. Field of the Invention
The present invention relates to a bellows-type hydraulic accumulator capable of absorbing a pulsation component from pressurized liquid.
2. Description of the Related Art
A conventional hydraulic accumulator of the described type includes a shell that defines a pressure space, a bellows unit that can be extended and contracted and is disposed within the pressure space, and a stay that has a communication port and is disposed within the bellows unit. One end of the bellows unit is fixedly secured to one end wall of the shell in order to divide the pressure space into an outer chamber serving as a gas chamber, in which a pressurized gas is enclosed, and an inner chamber serving as a liquid chamber communicating with a liquid inlet/outlet port formed in the end wall of the shell. The stay is disposed in the liquid chamber in order to restrict the degree of contraction of the bellows unit and to divide the liquid chamber into a fixed-volume liquid chamber having a fixed volume and a variable-volume liquid chamber whose volume is variable and which communicates with the fixed-volume liquid chamber via the communication port (see, for example, Japanese Patent Application Laid-Open (kokal) No. 2001-116003).
The above-described conventional bellows-type hydraulic accumulator operates as follows. Pressurized liquid discharged from a pump and containing a pulsation component which will cause vibration and noise flows into the accumulator via the liquid inlet/outlet port formed in the end wall of the shell. In the accumulator, the pressurized liquid flows from the fixed-volume liquid chamber formed between the shell and the stay to the variable-volume liquid chamber formed between the bellows unit and the stay via the communication port of the stay. The pressurized liquid having flowed into the variable-volume liquid chamber flows to the fixed-volume liquid chamber via the communication port of the stay, and then flows to the outside of the accumulator via the liquid inlet/outlet port formed in the end wall of the shell. Therefore, the pressurized liquid discharged from the pump and containing a pulsation component hardly flows into the variable-volume liquid chamber of the accumulator, and therefore, the accumulator may fail to efficiently absorb the pulsation component of the pressurized liquid discharged from the pump, which component is a cause of generation of vibration and noise.